Apparatus for measuring electromagnetic characteristics of a very high temperature material

Abstract

The apparatus comprises a waveguide having one end with an outside rim in the form of a test flange having a plane front surface defining a calibration plane and intended to be applied against a plane surface of a sample of material to be tested, a generator coupled to the waveguide to inject microwaves therein, and means for detecting the waves reflected by the material. At least the terminal portion of the waveguide including the test flange for application against the material to be tested at very high temperature is made of an electrically conductive refractory composite material, such as a carbon/carbon or a carbon/ceramic composite material.

I claim: 
     
       1. Apparatus for measuring electromagnetic characteristics of a material at a temperature of at least 1000° C., the apparatus comprising a waveguide having one end with an outside rim in the form of a test flange having a plane front surface defining a calibration plane and adapted to be applied against a plane surface of a sample of material to be tested, a generator coupled to the waveguide to inject microwaves therein, and means for detecting the waves reflected by the material, wherein at least the terminal portion of the waveguide including the test flange adapted for application against the material to be tested at a temperature of at least 1000° C. is made of an electrically conductive refractory composite material. 
     
     
       2. Apparatus according to claim 1, wherein the terminal portion of the waveguide is made of a composite selected from carbon/carbon and carbon/ceramic. 
     
     
       3. Apparatus according to claim 1, further including holding parts connected to the test flange of the terminal portion of the waveguide and intended to hold a sample of material to be tested against the flange, said holding parts being made of a refractory composite material. 
     
     
       4. Apparatus according to claim 1, including means for exposing a sample of material to be tested to a thermal flux on its side opposite from its side applied to the test flange of the terminal portion of the waveguide.